Commonly assigned application Ser. No. 258,708, filed Apr. 29, 1981, describes catalyst systems for ammoxidizing propylene to produce acrylonitrile and for carrying out other oxidation-type reactions such as the oxidation of unsaturated olefins to produce the corresponding aldehydes and acids and the oxydehydrogenation of various olefins to produce diolefins.
The catalyst systems described in that patent application comprise bismuth cerium molybdate oxide complexes promoted with one or more specific promoting elements. One such promoter is antimony.
Further research has shown that the antimony-promoted bismuth cerium molybdates show excellent catalytic properties when initially used in the ammoxidation of propylene and isobutylene. Unfortunately, it has been found that the ability of these catalysts to produce acrylonitrile and methacrylonitrile drops off significantly with time.
Accordingly, it is an object of the present invention to provide an improvement in the antimony-promoted bismuth cerium molybdates of Ser. No. 258,708 whereby the tendency of the catalyst to lose effectiveness over time is significantly reduced.
In addition it is further object of the present invention to provide new catalysts which are also useful in other oxidation-type reactions such as the oxidation of acrolein and methacrolein to produce the corresponding unsaturated aldehydes and acids and the oxydehydrogenation of various olefins such as isoamylenes to produce the corresponding diolefins such as isoprene.